Contour cutting apparatus

ABSTRACT

A work feeding apparatus for power tools of the class having a cutting tool operating in a fixed zone of a stationary work table. A pair of opposed guide means fixed on opposite sides of the tool zone define a channel through which successive work pieces advance to be cut by the tool, the pair of guide means being of a predetermined profile to effect cutting of a desired straight and/or curved contour in each work piece. A pair of power-driven feed rolls are positioned at entrance and exit ends of the channel, each being independently biased into driving engagement with the work piece to accommodate varying angularities of the work piece relative to the tool. The pair of feed rolls are also counterbalanced to be equally offset from the blade during straight cuts in the work piece. The feed roll at the entry to the channel is yieldably linked to an opposing counterpressure roll to augment the force of the entry feed roll in feeding the work piece while decreasing frictional resistance of the guide means to passage of the work piece. The pair of drive rolls are drivingly coupled together by a means including a limited lost motion to accommodate a difference in angular speed of one of the rolls in transition from an idle to a driving phase.

United States Patent VanSickle 1 Aug. 22, 1972 [54] CONTOUR CUTTINGAPPARATUS [72] Don C. VanSickle, 1435 Northview Place, Redlands, Calif.92373 Filed: Sept. 30, 1970 Appl. No.: 76,783

Inventor:

[56] References Cited UNITED STATES PATENTS 6/ 1917 Littleford ..144/242R X 2,552,367 5/ 1951 Carlson 144/242 R X 3,376,908 4/ 1968 VanSickle144/242 R FOREIGN PATENTS OR APPLICATIONS Primary Examiner-Andrew R..Iuhasz Assistant ExaminerMichael Koczo, Jr. Att0rneyFulwider, Patton,Rieber, Lee & Utecht Japan ..144/242 R [57] ABSTRACT A work feedingapparatus for power tools of the class having a cutting tool operatingin a fixed zone of a stationary work table. A pair of opposed guidemeans fixed on opposite sides of the tool zone define a channel throughwhich successive work pieces advance to be cut by the tool, the pair ofguide means being of a predetermined profile to effect cutting of adesired straight and/or curved contour in each work piece. A pair ofpower-driven feed rolls are positioned at entrance and exit ends of thechannel, each being independently biased into driving engagement withthe work piece to accommodate varying angularities of the work piecerelative to the tool. The pair of feed rolls are also counterbalanced tobe equally offset from the blade during straight cuts in the work piece.The feed roll at the entry to the channel is yieldably linked to anopposing counterpressure roll to augment the force of the entry feedroll in feeding the work piece while decreasing frictional resistance ofthe guide means to passage of the work piece. Thepair of drive rolls aredrivingly coupled together by a means including a limited lost motion toaccommodate a difference in angular speed of one of the rollsintransition from an idle to a driving phase.

11 Claims, 11 Drawing Figures Patented Aug. 22, 1972 3,685,556

3 Sheets-Sheet 1 INVENTOR. I 00/6? V/IA/5/C/(LE BY (g d/w m l PatentedAug. 22, 1972 3,685,556

3 Sheets-Sheet 2 I NVEN TOR. [Do/v0 K4AA5 CK4E QZM M, M

2% mid Z/d/ Mrraewa s Patented Aug. 22, 1972 3,685,556

3 Sheets-Sheet 5 INVENTOR Dav C? VAA/fl/CA Li {W pm,

CONTOUR CUTTING APPARATUS The present invention relates to apparatus forautomatically cutting contours through elongate work pieces by feedingthem to a tool operating in a fixed zone and constitutes an improvementover my prior US. Pat. No. 3,376,908. While the invention has specialutility in connection with band saws, it is of general utility withrespect to machine tools of this class.

FIG. 1 is a perspective view of a band saw incorporating a presentlypreferred embodiment of the invention.

FIG. 2 is a top plan view of the work feeding apparatus, alsoillustrating a work piece in various phases of transition therethrough,

FIG. 3 is a sectional view, on an enlarged scale, taken on the line 33of FIG. 2 and showing a portion of the drive mechanism for one of thefeed rolls.

FIG. 4 is a bottom plan view of the work table.

FIG. 5 is a sectional view, on an enlarged scale, taken on the line 5-5of FIG. 2, illustrating details of construction of a means forindependently biasing one of the feed rolls.

FIG. 6 is a sectional view, on an enlarged scale, taken on the line 66of FIG. 8 and illustrating details of construction of an entry feed rolland opposed counterpressure roll.

FIGS. 7 through 10 are somewhat schematic top plan views of the workfeeding apparatus, illustrating the relationship of the parts in variousphases of the transition of a work piece therethrough.

FIG. 11 is a perspective view of the contour-cut, severed portions of awork piece, shown assembled as a tree stand.

In the drawings, the invention is illustrated in a form especiallyadapted for woodworking and, further, especially adapted forlongitudinally severing straight lengths of wood along a straight andcurved contour line to make two portions that can be assembled into thewell known form of a tree stand. However, it will be understood that theinvention is not limited to this particular application but may beemployed with other machine tools and on other materials for cuttingother contours.

Referring to FIG. 1, a conventional band saw 10, with the usual endlessblade 11, includes'a base 12 on which a work table 13 is fixedlymounted. As will be apparent, the invention may be an integral part ofthe band saw but, customarily, takes the form of an attachment. Ineither event, the table 13 is provided with a slot 14 extending from oneedge of the table to the mid-line thereof and terminating in an enlargedopening 15. With this arrangement, the slot 14 provides clearance forthe saw blade 11 in removing and replacing a blade. The enlarged opening15 defines the fixed zone through which the blade runs.

This form of the invention is adapted for cutting elongate blocks ofwood 16 into two longitudinally severed portions 16a and 16b. As can beseen from FIG. 11, the two portions of the work piece 16 have beensevered out of a rectangular block along a contour line that includes apair of radius cuts at opposite ends of a relatively long straight cut,the line of severance commencing and terminating in the same plane ofthe original block of wood 16. The arrangement of the feed apparatus issuch that successive work pieces 16 may be fed therethrough practicallyin endto-end relationship, with a minimum of idle time of the blade 11,whereby an extremely high rate of production can be achieved.

The table 13 is provided on its upper face with a pair of guideassemblies 20 and 21. These assemblies are fixedly mounted on the plate13, on opposite sides of the hole 15 through which the blade 11 runs, todefine a generally arcuate channel extending transversely of the table13. The arrangement is such that confronting portions of the guideassemblies 20 and 21, along with the surface of the work table 13included therebetween and in association with the feed rolls, constraineach block of wood 16 for straight and curved linear movementtherethrough along a line of intersection with the blade 1 1 resultingin the curved and straight line cuts illustrated in Flg. 11.

More specifically, the concave guide assembly 20 comprises an identicalpair of elongate rigid bars 23 that are held in vertically spaced apartparallel superposed relationship, as by means of a spaced plurality oftubular sleeves 24. To hold the pair of bars 23 in assembledrelationship and onto the table 13, suitable screw fasteners 25 arepassed through aligned holes in the bars 23 and corresponding ones ofthe spacer sleeves 24 and threadedly engaged with bores in the table 13.

Similarly, the convex guide assembly 21 comprises an identical pair ofelongate plates 26, also arranged in congruent vertically spaced apart,parallel relationship by a plurality of the spacer sleeves 24 andfixedly held in place on the work table 13 by means of fasteners 25.

The confronting portions of the guide assemblies 20 and 21 are made witha profile adapted to produce the particular form of contour out which isdesired, which may be simply a straight line cut, curved cuts ofconstant or varying radii, or combinations of straight and curved cuts.Thus, for purposes of the tree stand in FIG. 11, the confronting edgesof the pairs of plates 23 and 26 are made with the profiles best seen inFIGS. 7 through 10.

Each bar 23, on its edge confronting the blade 11, has a concave curvedprofile 23a comprising anarc of a circle subtending the major portion ofthe length of the bar 23 and terminating at opposite ends in flatportions 20b and 200 oriented in parallel offset relationship to theplane of the blade 11. It will be observed that the cutting or workingedge of the blade 11 is disposed substantially at the mid-line of thetable 13 and the guide profile of the bars 23 is symmetrical about thismidline.

The guide assembly 21 may be adapted for either sliding or rollingcontact with the work piece 16. In either event, that portion of theguide assembly 21 confronting the guide assembly 20 or provided with anintermediate convex sector substantially defining a curve or arc that isgeometrically similar to the curved sector 23a of the guide bars 23.Thus, in a sliding arrangement, each of the plates 26 along its edgeconfronting a bar 23, may be formed with a curved portion 26a ofconstant radius to define an arc concentric with the sector 23a of theopposing bar and of equal angularity. The opposite terminal edgeportions 26b and 260 of each plate 26 are arranged tangentially to theintermediate curved portion 26a.

For rolling engagement of the work piece with the guide assembly 26,which is preferable, a plurality of rollers 27 may be arranged invertically disposed posian entry feed roll 30 and an exit feed roll 31.As the work pieces 16 may vary considerably from a nominal thickness,both of the feed rolls 30'and 31 are provided with a biasing meanswhereby they normally protrude into the channel defined between theguide assemblies 20 and 21. As a work piece 16 progresses through theapparatus, itis engaged first by the entry feed roll 30,thensimultaneously by'the pair of feed rolls and 31, a

and, finally, solely by the exit feed roll 31. Accordingly, each of therolls 30 and 31 is independently self adjustableto the thickness'of theparticular work piece passing through the apparatus during phases whenthe workpiece is being driven by one only of the rolls.iDuring anintermediate phase of the operation, when the work piece is being drivenby both rolls 30 and 31, the pair of rolls are self counterbalancing andadjust in unison to the particular thickness of the work piece.

More particularly, each of the feed rolls 30 and 31 is mounted on one ofa pair of symmetrically arranged bell cranks 32 and 33, each of which ispivotally mounted on the top of the table 13. Since the manner ofmounting the bell cranks. is the same, only one mounting arrangementwill be described.

Referring to FIG. 3, the table l3is formed with a hole which mounts asleeve bearing 35 that is externally formed with a flange 36 adapted toseat on the upper surface of the table and, further, adapted to receivea fastening means'for securing the bearing to the table. The bell crank32, at the intersection of its two arms, is integrally formed with asleeve 37 that is pivotally mounted in the bushing 35. The sleeve 37, inturn, mounts a spaced pair of bushings 38 to provide journal bearingsupport for an elongate shaft 39 that protrudes beyond both the upperand lower ends of the sleeve 37, in order to mount sprocket wheels 40and 41, respectively.

To mount a feed roll, the bell crank 32, at the swingable end of itsouter arm, is formed with a slot 43 to receive a reduced diameterthreaded shank of a stud bolt 44 that is secured in place by means of anut 45. The roll 30 comprises a pair of wheels 47 and 48 flank-, ingopposite sides of a sprocket wheel 49, the wheels preferably, but notnecessarily, having peripheral teeth. The wheels 47 and 48 areco-axially mounted on a bushing 50 rotatably supported on the stud ofthe bolt 44, with the pair of toothed wheels and the sprocket ciently toavoid contact with the work piece 16 when the piece is engaged by theteeth of the'wheels 47 and 48. The small sprocket 40 is keyed to theshaft 39 which, in turn, is drivingly interconnected to a chain at itslower end.

The mounting of the otherfeed roll 31 to its bell crank 33 is in allrespects identical to that just described in connection with thefeedroll30, except that the shaft 39 for the exit end roll 31 is directlykeyed to a sprocket wheel 55 at'itslower end, as can be seen in FIG. 4.By contrast, the sprocket wheel 41 for the entry feed roll is drivinglyinterconnectedto its shaft with a limited degree of lost motion.

Referring again to FIG. 3, it will be seen that the shaft 39, at itslower end, has a diametrically extending cross .bar 57 secured thereto,as by means of a crossing pin 58. The lower end face of thesprocketwheel 41 fixedly'mounts a diametrically opposite pair of drivelugs 59 that project axially. to engage opposite sides of the cross bar57. The relationship of the drive lugs 59 to the cross bar 57 can bestbeseen in FIG. 4. As will now be apparent, the arrangement is suchthat'a limited degree of relative angular movement is permitted betweenthe shaft 39 and its cross bar 57, on the one hand, and the.

sprocket wheel 41,- on the other hand. Thus, assuming clockwise rotationofthe sprocket wheels 41 and 55, as viewed in Fig. 4, the drive lugs 59of the sprocket wheel 41 are engaged in pockets 60 formed in oppositeedges rotation of their drive shafts 39,are .not always the same.Accordingly, upon any difl'erential occurring, one of the sprocketwheels 41 and55, in effect, over-- running the other, the limited degreeof relative angular movement permitted between-the drive lugs 59 andthe. cross bar 57 compensates for the difierence without undulystressing the interconnected parts of the drive mechanism.

wheel 49, being fixedly secured together, as by means of v a fastener51. It will be noted that the sprocket wheel 49 is substantially smallerin diameter than the toothed wheels 47 and 48 and is drivingly engagedby an endless As will be apparent, the drive rolls 30 and 31 may bedriven from any convenient power source. For example, a variable speedelectrical motor'65 may be coupled to a reduction gear box 66 mounted ontop of the table 13, the gear box, in turn, having an output shaft 67protruding from the bottom of the table, as shown in FIG. 4. A drivesprocket wheel 68 is keyed to the output shaft 67 and drivinglyinterconnected to an endless chain 69 that is trained around thesprocket wheels41 and 55, as well as around an idler sprocket wheel 70.

The biasing means for the'drive rolls 30 and 31 is mounted on'top of theplate 13 by means of a bracket '75. A pair of. upstanding lugs 76 areintegrally formed at opposite ends of the bracket, the lugs being formedwith holes therethrough having a common axis disposed on the mid-line ofthe table 13. A shaft 77 is axially slidably mounted in the holes of thepair of lugs 76, having a portion projecting 'rearwardly of the rear lug76 for mounting a helical spring 78 in compression between the rear faceof the rear lug 76 and a nut and washer abutment 79 mounted on the rearend of the shaft 77. With this arrangement, a T-shaped yoke 80, securedto the forward end of the shaft 77, is normally biased against the frontface of the forward lug 76.

Each of the oppositely extending arms of the T- shaped yoke 80 is formedwith a horizontally elongated slot therethrough to horizontally rockablymount an elongate threaded rod 82. The forward end of each rod 82 mountsa clevis 84 that receives the swingable end of the inner arm portion ofone of the bell cranks 32 and 33, the clevis and its corresponding bellcrank being pivotally interconnected by a fastener means 85. The rearend of the rod 82 threadedly mounts a nut 86 to a seat for a washer 87providing an opposing abutment for the rear face of the correspondingarm of the yoke 80. A helical spring 88 is mounted between the opposedabutments so defined, under compression, to pivot the corresponding bellcrank 32 or 33 for normally biasing its associated feed roll into thepath of work pieces moving through the apparatus. As will be apparent,the nuts 86 can be adjusted to equalize the compression of the pair ofsprings 88.

Each rod 82 is reciprocable relative to the yoke 80 within apredetermined range as determined by spaced pairs of stop nuts 90 and 91threadly engaged with the rod on opposite sides of an arm of the yoke80. As will be apparent from an examination of FIGS. 7 through 10, theposition of the pair of nuts 90 axially of a rod 82 determines theextent to which the corresponding feed roll can protrude into thechannel between the guide assemblies and 21. The pair of nuts 91 of bothrods 82 are so adjusted as to come into abutment with the rear face ofthe arms of the yoke 80, in order to unseat the yoke from the front faceof the front bracket lug 76 during that phase of the sequence ofoperations when both feed rolls are drivingly engaged with the workpiece 16.

From an examination of FIGS. 7 through 10, it will be observed thatthere is an initial phase in which the work piece is fed to the blade 11solely by' the entry feed roll 30, the exit feed roll 31 being idle inthe sense that it is not in driving engagement with the work. Duringthis phase, the work piece is undergoing a radius cut and, in transitionfrom the first radius cut to the straight cut, must displace the exitfeed roll 31. Throughout this phase, one edge of the leading end of thework piece 16 is in sliding frictional engagement with the exit half ofthe curved sector 23a of the guide assembly 23 with a force proportionalto the pressure of the entry feed roll 30 against the confronting sideof the work piece 16. In order to reduce this friction in this phase ofthe operation, without loss of feeding force, I have devised acounterpressure roll arrangement operatively as sociated with the entryfeed roll 30.

Referring to FIG. 6, it will be seen that the stud bolt 44 that mountsthe feed roll 30 is integrally formed with a downwardly projectingextension 95 that is freely swingable in an arcuate slot 96 formedthrough the table 13. Beneath the table, the extension 95 has anabutment member 97 pivotally secured thereto for comovement with theextension 95. The member 97 is formed with a horizontal bore throughwhich a threaded rod 98 is freely mounted, the rod being orientedtransversely of the passage between the pair of guide assemblies 20 and21. That end of the rod 98 underlying the feed roll 30 mounts a nut 99and washer 100 providing a fixed abutment for one end of a helicalspring 101 around the rod 98, the other end of the spring abuttingagainst one side of the member 97.

The other end of the rod 98, underlying the guide assembly 21, isinterconnected to or fixedly interconnected to a yoke 102 that ispivotally interconnected, as at 103, to the swingable end of a lever104, the latter being clamped to the lower end of a vertical shaft 105that is journaled in the pair of plates 26 of the guide assembly 21.

Between the guide plates 26, the shaft 105 carries a crank arm 106 whoseorientation can best be seen in FIG. 2, the arrangement being such thatthe crank am 106 substantially overlies the lever 104 beneath the plate13. Mounted on the swingable end of the crank arm 106 is a roller 107 inopposed relationship to the entry feed roll 30.

With the arrangement just described, the pressure roller 107 isyieldably linked to the entry feed roll 30 in order to change positionlaterally with respect to the channel between the guide assemblies 21and 20, along with change of position of the feed roll 30, while at thesame time being firmly spring biased into pressure engagement with theopposite side of the work piece 16 from the feed roll 30.

The rod 98, in the length between the member 97 and the pivotalconnection 103, carries a lock nut means 110 against which the member 97is normally biased by the spring 101, when no work piece is v disposedbetween the pressure roller 107 and the feed roll 30. This condition isillustrated in FIG. 4 and the lock nuts are initially adjusted axiallyof the rod 98 to a position wherein a minimum gap is defined between theroller 107 and the drive roll 30, which is less than the least thicknessof the work piece 16 which is to be encountered. Upon a work piece 16being fed between roller 107 and the drive roll 30, as in FIG. 7, thespring 101 is immediately compressed as a result of the initialdisplacement of the roller 107. Subsequently, as the feed roll 30 isdisplaced laterally by the work piece 16, as in FIG. 8, the pressureroller 107 also swings outwardly and is constantly forceably biased intocontact with the opposite side of the work piece by the continuingcompressed state of the spring 101. As a result, the friction of thatedge of the leading end of the piece 16 against the exit halves of thecurved sectors 23a is reduced without loss of work feeding force.

The apparatus can handle any length of work in excess of a minimumlength capable of being simultaneously engaged by the feed rolls 30 and31 at their maximum lateral separation. From an examination of FIG. 9,it will be seen that the maximum width of work piece which can beaccommodated is equal to the normal distance between a plane includingthe opposite end portions'23b and 230 of the guide assembly 20 and aparallel plane tangent to the confronting portion of the guide means 21,in this case tangent to the periphery of the roller 28 protruding beyondthe plates 26.

Initially, the apparatus is set up or adjusted to handle the nominalthickness of the work pieces 16. First, the pair of side springs 88 areremoved to allow free pivotal movement of the bell cranks 32 and 33 andthe feed rolls 30 and 31 supported thereon. A specimen of the work piece16 is then centered in the apparatus as shown in FIG. 9. Thereafter, thepairs of stop nuts 91 are adjusted for engagement with the yoke 80simultaneously with simultaneous engagement of the feed rolls 30 and 31within the work piece 16, while the With the sample work piece 16removed, the pairs of stop nuts 90 are now adjusted for adjusting thepositions of the feed rolls 30 and 31 relative to the convex guide means21 to define equal gaps less than the least thickness of work piece 16to be encountered. Finally, the spring pressure for the counterpressureroller 107 is adjusted inthe manner previously described. As will beapparent, the finally adjusted positions of the parts may .varyconsiderably, depending on the thickness of the work pieces beinghandled. Thus, the parts 4 as represented in FIG. 2represent'a differentstate of adjustment than is represented in FlGS. 7 through 10.

As the leading end of a work piece 16 is introduced into the apparatus,it is subjected to the opposed pressures of thefeed roll 30 andthecounterpressure roll 107 and forced to the position of the workpieceshown in FIG. 7, wherein one edge of the leading end of the work piecefirst engages the concave guide assembly 20 at about the axis ofsymmetry. The entry feed roll has now beendisplaced inducing compressionin its associated spring 88, as well as compression of thecounterpressure roller spring 101, for firmly. forcing the work piecethrough the first radius cut.

As the first radius cut progresses, as in Hg. 8, the

entry feed roll'30 and the counterpressure roller 107 l inkedlyconnected thereto, are progressively displaced towards the guideassembly 20, effecting a further compression of the spring 88 associatedwith the entry feed roll. During this phase, depending upon the relativecompression of the counterbalanced pair of springs 88 and the centerspring 78,'the yoke 80 may be displaced from the front lug 76, although,under some conditions, such unseating of the yoke 80 will not occuruntil the work piece 16 comes into the straight cut position of FIG. 9.In. the 'case of a relative compression of the springs as illustrated inFIG. 8, it will be observed that the balance of forces is such that theexit feed roll 33 is being displaced prior to the leading edge of thework tion at 26c acting in opposition to the entry half of the contour23c engaged by one end of the trailing edge of the work piece and theexit feed roll 31. As will be apparent from FIG. 10, the work pieces 16may be fed in practically end-to-end relationship since the entry feedroll 30 is now repositioned in readiness to accept a new work pieceprior to the completion of the second radius cut in the prior workpiece.

While a presently preferred embodiment of my invention has been shownand described, it will be apparent to those skilled in the art thatmodifications may be made therein without departing from the invention.

I claim: I

1. Work feeding apparatus for contour cutting of elongated work pieces,comprising:

a work table having a fixed tool zone;

a spaced pair of rigid guide means affixed to said 1 table to define alaterally extending work piece passage therebetween and through saidtool zone; a pair of feed rolls mounted on said table at spacedlocations on opposite sides of said tool zone and along one of saidguide means; v

each of said feed rolls being mounted for movement towards and away fromthe other of said guide means; g

said pair of feed rolls being independently biased toward the other ofsaid guide means to bias a work piece into guided contact'with saidother guide means independently of the other .of said feed rolls; 1

said pair of feed rolls each normally projecting into said passagedefined by said pair of guide means to be sequentially laterallydisplaced by a workpiece fed thereinto; and

a means for driving said feed rolls to feed a work piece through saidtool zone.

2. An apparatus as in claim 1 in which:

said pair of guide means def'me a curved sector in saidpassagecomprising a convex portion of said I other guide means and a concaveportion of said one guide means,

said portions being adapted to translate linear move-.

4. An apparatus as in claim 3 in which each of said 7 rolls isinterconnected to a spring means for indepen dently biasing said rollinto contact with a work piece, each of said spring means including ameans to adjust the force thereof whereby the pair of said spring meanscan be counterbalanced. i

5. Am apparatus asin claim 1 in which: I a counterpressure roller ismovably mounted on said table in opposition to one of said feed rolls atan entry end of said passage; said one feed roll and said roller beingyieldably interconnected by a means adapted to translate displacement ofsaid one feed roll by a work piece into corresponding displacement ofsaid roller and further adapted to bias said roller against a work pieceduring such displacement of said roller. 6. An apparatus as in claim 5in which said means interconnecting said roller and said one feed rollcomprises a linkage including a spring means that normally biases saidroller and said one feed roll toward one another.

7. An apparatus as in claim 1 in which said pair of feed rolls aresimultaneously driven by said power means, one of said feed rolls beinginterconnected to said power means by an overrunning clutch means.

8. An apparatus as in claim 1 in which:

said one guide means includes a concave sector;

said pair of feed rolls being adapted to normally project radiallyinwardly of tangents to the opposite ends of said concave sector;

said pair of feed rolls each having a mounting means adapted toselectively positively limit such radially inward projection of saidfeed rolls.

9. An apparatus as in claim 8 in which:

said other guide means includes a convex sector in confrontingrelationship to said concave sector;

said convex sector being defined by a plurality of rollers adapted forsequential rolling engagement with one side of a work piece;

said concave sector being defined by a continuous rigid surface adaptedfor sliding engagement with an edge of an opposite side of a work piece;

one of said feed rolls at an entry end of said passage beinginterconnected to a counter-pressure roller;

said one feed roll and said roller being yieldably interconnected by ameans adapted to translate displacement of said one feed roll by a workpiece into corresponding displacement of said roller and further adaptedto bias said roller against the opposite side'of the work piece fromsaid one feed roll during such displacement of said roller.

10. An apparatus as in claim 1 in which:

each of said feed rolls is mounted on an end of one arm of a bell crank;

said bell crank having one end of a second arm interconnected to aspring biased rod adapted to bias the corresponding one of said rollsinto forceful engagement with a side of a work piece.

11. An apparatus as in claim 10in which each of said rods is mounted onopposite sides of a yoke, said yoke being mounted on a spring biasedshaft adapted to simultaneously bias said pair of feed rolls against awork piece.

1. Work feeding apparatus for contour cutting of elongated work pieces,comprising: a work table having a fixed tool zone; a spaced pair ofrigid guide means affixed to said table to define a laterally extendingwork piece passage therebetween and through said tool zone; a pair offeed rolls mounted on said table at spaced locations on opposite sidesof said tool zone and along one of said guide means; each of said feedrolls being mounted for movement towards and away from the other of saidguide means; said pair of feed rolls being independently biased towardthe other of said guide means to bias a work piece into guided contactwith said other guide means independently of the other of said feedrolls; said pair of feed rolls each normally projecting into saidpassage defined by said pair of guide means to be sequentially laterallydisplaced by a work piece fed thereinto; and a means for driving saidfeed rolls to feed a work piece through said tool zone.
 2. An apparatusas in claim 1 in which: said pair of guide means define a curved sectorin said passage comprising a convex portion of said other guide meansand a concave portion of said one guide means; said portions beingadapted to translate linear movement of a work piece through saidpassage into turning of the work piece for arcuate cutting of the workpiece; said pair of feed rolls being adapted and arranged forsimultaneously biasing a work piece against said convex portion duringone phase of the work piece movement through said passage.
 3. Anapparatus as in claim 2 in which said pair of feed rolls areinterconnected by a common biasing means to simultaneously bias both ofsaid rolls into engagement with a work piece.
 4. An apparatus as inclaim 3 in which each of said rolls is interconnected to a spring meansfor independently biasing said roll into contact with a work piece, eachof said spring means including a means to adjust the force thereofwhereby the pair of said spring means can be counterbalanced.
 5. Anapparatus as iN claim 1 in which: a counterpressure roller is movablymounted on said table in opposition to one of said feed rolls at anentry end of said passage; said one feed roll and said roller beingyieldably interconnected by a means adapted to translate displacement ofsaid one feed roll by a work piece into corresponding displacement ofsaid roller and further adapted to bias said roller against a work pieceduring such displacement of said roller.
 6. An apparatus as in claim 5in which said means interconnecting said roller and said one feed rollcomprises a linkage including a spring means that normally biases saidroller and said one feed roll toward one another.
 7. An apparatus as inclaim 1 in which said pair of feed rolls are simultaneously driven bysaid power means, one of said feed rolls being interconnected to saidpower means by an overrunning clutch means.
 8. An apparatus as in claim1 in which: said one guide means includes a concave sector; said pair offeed rolls being adapted to normally project radially inwardly oftangents to the opposite ends of said concave sector; said pair of feedrolls each having a mounting means adapted to selectively positivelylimit such radially inward projection of said feed rolls.
 9. Anapparatus as in claim 8 in which: said other guide means includes aconvex sector in confronting relationship to said concave sector; saidconvex sector being defined by a plurality of rollers adapted forsequential rolling engagement with one side of a work piece; saidconcave sector being defined by a continuous rigid surface adapted forsliding engagement with an edge of an opposite side of a work piece; oneof said feed rolls at an entry end of said passage being interconnectedto a counterpressure roller; said one feed roll and said roller beingyieldably interconnected by a means adapted to translate displacement ofsaid one feed roll by a work piece into corresponding displacement ofsaid roller and further adapted to bias said roller against the oppositeside of the work piece from said one feed roll during such displacementof said roller.
 10. An apparatus as in claim 1 in which: each of saidfeed rolls is mounted on an end of one arm of a bell crank; said bellcrank having one end of a second arm interconnected to a spring biasedrod adapted to bias the corresponding one of said rolls into forcefulengagement with a side of a work piece.
 11. An apparatus as in claim 10in which each of said rods is mounted on opposite sides of a yoke, saidyoke being mounted on a spring biased shaft adapted to simultaneouslybias said pair of feed rolls against a work piece.